Make Stunning Schenker Graphs with GNU Lilypond

and follow with all quarter notes or quarter-note skips, never rests. The second line becomes useful when adding slurs. Because slurs attach to the stem if the stem and slur are on the same side of the note, you can use this line to cause all slurs to attach only to noteheads. Just remember to cancel it out when you add a visible stem. When you reach the end of the voice, remember to \revert anything you \override.

Once the notes are added, you can begin adding the necessary slurs, beams and other appropriate marks. Multiple layers of slurs are intrinsic to Schenkerian notation, but they can be cumbersome in Lilypond code. There are two ways to accomplish it. The first is to use the phrasing slur tool. This allows you to create a lower layer of slurs with ( and ) and an upper layer with \( and \). This allows for only two layers of slurs, but it does let you keep both layers in the same voice. If two layers of slurs are all you need, this may help you keep your code cleaner and save you a little work.

If you need more than two layers—note the four layers of slurs on the first note in the Bach example—you must create multiple voices. If you require three layers of slurs, create three voices. In the first voice, begin with:

\override Stem #'transparent = ##t
\override Stem #'length = #0

as before, and follow this with all the notes in the line (and the skips and \revert commands). Insert the first (lower) layer of slurs in this voice.

In the second voice, begin with:

\override NoteHead #'transparent = ##t
\override Stem #'transparent = ##t
\override Stem #'length = #0

and follow with all the notes and the second layer of slurs. This attaches each slur to an invisible note in the same place as the visible notehead from voice one. If you want, you can replace the unneeded notes in this voice with skips, but it is unnecessary. The third voice will look like the second voice, but it will include only the third layer of slurs.

After making a few minor spacing adjustments, your code may look something like this (a variation of the beginning of the lower staff of the Bach example):

<<
  {
    \override Stem #'transparent = ##t
    \override Stem #'length = #0
    \once \override TextScript #'extra-offset =
      #'(-11 . -2.5)
    g4 a( b) fis( e)
    \revert Stem #'transparent
    \revert Stem #'length
    }
\\
  {
    \override NoteHead #'transparent = ##t
    \override Stem #'transparent = ##t
    \override Stem #'length = #0
    \once \override Slur #'extra-offset =
      #'(0.5 . 0.75)
    \once \override Slur #'height-limit = #1.5
    g4( a b) fis e
    \revert NoteHead #'transparent
    \revert Stem #'transparent
    \revert Stem #'length
    }
\\
  {
    \override NoteHead #'transparent = ##t
    \override Stem #'transparent = ##t
    \override Stem #'length = #0
    \slurDown
    \once \override Slur #'extra-offset =
      #'(-1.25 . 0)
    \once \override Slur #'height-limit = #2.75
    g4( a b fis e)
    \revert NoteHead #'transparent
    \revert Stem #'transparent
    \revert Stem #'length
    }
>>

Figure 3. Using layers of slurs helps you organize your code clearly.

Even when using only two layers of slurs, I prefer this method rather than using slurs and phrasing slurs combined. It gives me the same method in every graph, it organizes my code more clearly and when I edit slur properties, I always use the same commands for any layer. Otherwise, I would alternate between overriding slur properties and phrasing slur properties.

When using slurs in Schenker graphs—especially when using multiple layers—you likely will need to edit some of the slur properties in your graph. The simplest edits are \slurUp and \slurDown, which cause the following slur to be created above or below the notes, respectively, and \slurDashed, a new tool in Lilypond 2.6, which creates a dashed slur.

Another common tweak I find useful is:

\once \override Staff.Slur #'height-limit = #x

This allows me to specify how deep or shallow the slur should be drawn (represented by the value x), and it is especially helpful for layered slurs or for slurs under and over text. Occasionally, I have to specify the entire set of coordinates for a slur manually. This lets you create some funky slurs, which some Schenkerian theorists love to use. For that, use the following code, where x and y are horizontal and vertical distances, measured in staff lines:

\once \override Slur #'control-points =
  #'((x . y) (x . y) (x . y) (x . y))

And, as with just about any notational element in Lilypond, you can alter a slur's extra-offset property, moving the entire slur without altering the shape:

\once \override Slur #'extra-offset = #'(x . y)

See the example of slur layers in Figure 3 to observe extra-offset and height-limit in action.